Research Methods Core: Partnered research presents diverse methodological challenges. Drawing on diverse scientific paradigms and disciplines, we propose an Interdisciplinary Partnered Methods Core (or "Methods Core" for short) to support the mission of the proposed NIMH Partnered Research Center for Quality Care. Methodological input and development are relevant to every aspect of the Center. Specific needs include measuring participation and markers of network capacity, tracking outcomes for diverse stakeholders, monitoring feedback from partners and communities that relate to the Center's capacity to support partnered research, and evaluating intervention implementation and outcomes. We seek to ensure that efforts to advance knowledge and to inform programs and policy decisions are based on rigorous science as well as to promote two-way capacity building so that partners gain access to methodological expertise and methodologists are responsive to community needs and contexts. We have structured Units for this Methods Core to provide necessary expertise in design and quantitative analysis, qualitative and mixed methods techniques, measures development and adaptation to diverse populations, and policy analysis. Like the Core as a whole, each Unit (Biostatistics, Qualitative/Mixed- Methods, Measurement, Policy) is co-led by academic and partner Center members. The Qualitative/Mixed-Methods Unit includes a component to provide Rapid-Response Capability to assess research opportunities on a time scale that will facilitate taking advantage of potential natural experiments. Because we anticipate that future community-based partnered research will occur within network contexts, we have proposed an R34 Methods Pilot that will develop a web-based networking tool that, in addition to enhancing our network-analysis capabilities for research purposes, can be expected to support efforts to enhance quality of care by strengthening agency networks, particularly in an area of need we have identified regarding: mental-health services for individuals with co-occurring (notably substance-use) disorders. Training of. students and emerging investigators remains a.central goal of the Methods Core, and our Policy Unit includes support for a newrinvestigator pilot study onutility assessment for cost-effectiveness analysis in community programs for severe mental illness. , Overall;we plan to provide high-quality biostatistical support for partnered research, sophisticated qualitative/mixed-methods support for intervention development and evaluation, expert-supported development and application of measures of quality and outcomes of care that are appropriate for diverse populations, and state-of-the-art application of policy-analysis insights both in specific domains of quality-ofcare research as well as in the review of all Center projects for policy relevance.